Who Was St. Gregory of Nazianzus? The Theologian of the Trinity

The Orthodox Church gives the title "the Theologian" to very few saints. The first is the Apostle John. Another is St Gregory of Nazianzus, who earned it as a preacher. Between 379 and 381, in a small chapel in Constantinople where the few Christians loyal to the Creed of Nicaea gathered, he gave five sermons on the Holy Trinity that the Church has read ever since. When Orthodox Christians confess the Holy Spirit as God, they use words Gregory defended when much of the capital disagreed.

He was an unlikely hero who wanted quiet and prayer and kept being pushed into offices. He was ordained priest against his will, consecrated bishop of a village he never governed, enthroned in the capital by the emperor himself, and then resigned during the council now counted as the Second Ecumenical Council. This article tells his life as the Church remembers it, then asks what the sources allow us to verify.

In brief

Gregory was born in Cappadocia (in modern Turkey) around 329 or 330 and died around 390; the sources disagree by a few years at each end. He studied at Athens with Basil of Caesarea, was ordained priest by his father against his will, and was made bishop of Sasima by Basil, a see he never governed. In 379 he went to Constantinople to lead a small Nicene congregation in a house-chapel he called the Anastasia ("Resurrection"), and there he preached the Five Theological Orations. Theodosius enthroned him in the city's main church in late 380; in 381 he briefly presided over the council later received as ecumenical, then resigned. Most of what we know comes from his own orations, letters and poems, so the record is rich but told largely from his side. The Orthodox Church keeps his feast on 25 January and, with Basil and John Chrysostom, on 30 January.

Thesis: Gregory's life is better documented than that of almost any saint of his century, largely by his own pen, and his teaching on the full divinity of the Holy Spirit and the monarchy of the Father remains one of the clearest early statements of the faith Orthodox Christians confess today.

The life as the Church remembers it

Nazianzus and Athens

Gregory's father, also named Gregory, was bishop of Nazianzus, and his mother, St Nonna, is remembered for having prayed for a son and promised him to God.¹ He studied at Caesarea, Alexandria and then for many years at Athens, where he came to know Basil "more perfectly." Remembering those years in his funeral oration for Basil, Gregory said, "We seemed to have one soul, inhabiting two bodies."² Among their fellow students was the future emperor Julian, later called the Apostate.³ He was not baptized as an infant, and when he was baptized is uncertain: during a storm at sea, as some biographers thought, or after returning home.⁴

A priest against his will

Gregory wanted the ascetic life he had tasted with Basil in Pontus, but his aging father, with the congregation's loud approval, ordained him priest, probably at Christmas in 361. Gregory fled back to Pontus, then returned for Easter and explained himself in his second oration, a long reflection on priesthood. Guiding human souls, he wrote, "seems to me in very deed to be the art of arts and science of sciences."⁵

Sasima and a wounded friendship

Around 370 Basil became metropolitan of Caesarea. When the emperor Valens divided Cappadocia into two provinces, Basil and Anthimus of Tyana quarreled over jurisdiction. Basil strengthened his hand by creating new bishoprics and consecrated Gregory, much against his will, to one of them, Sasima.⁶ His letters are bitter: "Why should I fight for sucking pigs and fowls, and those not my own, as though for souls and canons?"⁷ Anthimus occupied the town with troops, and Gregory probably never administered the see. He stayed at Nazianzus to help his father, who died in 374.⁸

He did not hide the wound even in his funeral oration for Basil. He admired Basil's "whole conduct," he said, but could not approve "the change and faithlessness of his treatment of myself, a cause of pain which even time has not obliterated."⁹

Constantinople and the Anastasia

After his father's death Gregory withdrew to the shrine of St Thecla at Seleucia in Isauria. In 379 the Nicene Christians of Constantinople, who had no church of their own after some forty years under non-Nicene bishops, asked him to come.¹⁰ Gregory began preaching in a private house he named the Anastasia. In his farewell sermon he addressed it: "Farewell my Anastasia, whose name is redolent of piety: for you have raised up for us the doctrine which was in contempt."¹¹

According to the Orthodox Church in America, on the night of Pascha in 379 a mob broke into the chapel while he was baptizing, and he was wounded.¹² St Jerome, who studied with him in these years, later called Gregory "my instructor in the Scriptures."¹³ He also befriended a Cynic philosopher from Alexandria named Maximus and preached in his praise, and Maximus then had himself secretly consecrated bishop of the city by Egyptian bishops while Gregory was ill.¹⁴ The council of 381 later declared "that Maximus never was and is not now a Bishop."¹⁵

In late November 380 the new emperor Theodosius entered Constantinople, ordered the non-Nicene bishop Demophilus to accept the Nicene Creed or give up the churches, and, when he refused, gave them to the Nicene party. The emperor himself accompanied Gregory to the city's great church, where he was enthroned.¹⁶

The council of 381 and his resignation

In May 381 Theodosius gathered about 150 bishops in Constantinople. Meletius of Antioch presided at first and, according to Theodoret, confirmed Gregory as bishop of the capital.¹⁷ Meletius then died, and Gregory took the chair. He urged the bishops to end the schism at Antioch by letting the elderly Paulinus keep that see for life. They refused. Late-arriving Egyptian and Macedonian bishops also objected that his move from another see broke the canons against transferring bishops. Gregory later likened the bishops' outcry to jackdaws and the younger members to a swarm of wasps.¹⁸

He resigned. His farewell oration is frank about the city: "they seek not for priests, but for orators, not for stewards of souls, but for treasurers of money."¹⁹ It ends with a litany of farewells, to his church, his people, the emperors and the angels, and to the Trinity itself: "Farewell, O Trinity, my meditation, and my glory."²⁰ Nectarius, an official of senatorial family who was still a catechumen, was chosen to succeed him.

Last years and poems

Gregory cared for the church of Nazianzus until a bishop, Eulalius, could be appointed, then retired to the family estate at Arianzus, where he wrote against the followers of Apollinarius and composed a great deal of poetry.²¹ Invited to another synod at Constantinople in 382, he declined; his English editors summarize his reason as a dislike of episcopal synods, from which he had never known any good to come.²² His long poem Concerning His Own Life is the main source for his years in the capital.²³ Jerome reports that his works ran to thirty thousand lines.²⁴

The Five Theological Orations

The five sermons now numbered Orations 27 to 31 were preached in the Anastasia against the followers of Eunomius, who claimed that God's essence could be grasped by logical reasoning. The first sets conditions for speaking about God at all: "Not to every one, my friends, does it belong to philosophize about God; not to every one; the Subject is not so cheap and low."²⁵ The second insists that God is beyond comprehension: "it is impossible to express Him, and yet more impossible to conceive Him."²⁶

The third and fourth turn to the Son, starting from the Father. Christians honor a "Monarchy," he says, but not one "limited to one Person"; the Father is "the Begetter and the Emitter," the Son is begotten and the Spirit proceeds, "without reference to time."²⁷ This is the monarchy of the Father: the Father is the one source of the Son and the Spirit, who share his one divine nature.

The fifth oration, on the Holy Spirit, is the boldest. Gregory takes the word "proceeds" from "the Spirit of truth who proceeds from the Father" (John 15:26, NKJV) and argues that the Spirit, "inasmuch as He proceeds from That Source, is no Creature; and inasmuch as He is not Begotten is no Son."²⁸ Then he says it outright: "Is the Spirit God? Most certainly. Well then, is He Consubstantial? Yes, if He is God."²⁹

His opponents accused him of going beyond Scripture. His answer: "The Old Testament proclaimed the Father openly, and the Son more obscurely. The New manifested the Son, and suggested the Deity of the Spirit. Now the Spirit Himself dwells among us, and supplies us with a clearer demonstration of Himself."³⁰ God revealed the Trinity gradually, he argues, so as not to overwhelm people.

In a sermon on baptism (early January 381, according to his English editors) he put the whole faith in two sentences: "No sooner do I conceive of the One than I am illumined by the Splendour of the Three; no sooner do I distinguish Them than I am carried back to the One."³¹ And writing to the priest Cledonius against Apollinarius, who denied that Christ had a human mind, he gave the Church a rule for thinking about the Incarnation: "For that which He has not assumed He has not healed."³² Christ took on the whole of human nature so that all of it could be healed and united to God: salvation as healing and theosis, in one line.

See also our articles on the Cappadocian Fathers and the profile of Basil the Great.

Why "the Theologian"?

His nineteenth-century English editors note that he shares the title "with S. John the Evangelist alone among the Fathers of the Church."³³ Many books say the Council of Chalcedon conferred it in 451. A 2019 study by Oliver Langworthy argues that this is too strong. The title appears in the Address to Marcian appended to the acts of Chalcedon, probably written by Theodoret of Cyrrhus, but Gregory "is not referred to as such in the minutes of the Council itself," and Langworthy found no evidence that the title was granted rather than simply used.³⁴ By the mid-fifth century the title was simply in use.

What can we actually verify?

(a) Contemporary and near-contemporary evidence

For a fourth-century saint the evidence is unusually rich. {{very-strong: Gregory's own orations, letters and autobiographical poems survive and give a first-hand account of his ordination, Sasima, his work in Constantinople and his resignation.}} Jerome, his pupil, writing about 392 or 393 (his catalogue runs to "the fourteenth year" of Theodosius), lists his works and says Gregory retired to the country and "died, three years or more ago."³⁵ The fifth-century historians Socrates and Theodoret describe 380 and 381, and the council's canons survive.

These sources do not always agree. Socrates places Gregory's resignation soon after the emperor arrived, because some murmured that he was a stranger, and, describing the council, says Gregory "had resigned that see." He also says the emperors later built a large church beside Gregory's oratory and named it Anastasia.³⁶ Theodoret puts Maximus's consecration after Meletius's death, during the council, while the Catholic Encyclopedia places it before Theodosius reached the city. Most of the detail depends on Gregory himself, and Concerning His Own Life is plainly a defense of his own conduct.

The dates are uncertain too. The Orthodox Church in America gives 329 for his birth and 25 January 389 for his death; the Catholic Encyclopedia (1910) gives about 325 to 389; CatholicCulture.org's Roman calendar page gives 330 to 390; and his nineteenth-century English editors, who argued he was born no earlier than 325 and probably not before 330, place his death in 391.³⁷ {{strong: He was born around 329 or 330 and died around 390.}}

(b) Later hagiographical tradition

Later lives mostly rearrange details from Gregory's own writings, such as Nonna's vow and the storm at sea. The joint feast of the Three Hierarchs rests on a later tradition: according to the Orthodox Church in America, the three saints appeared in 1084 to St John, bishop of Euchaita, to end quarrels among their admirers, and he set the joint feast on 30 January.³⁸ That is a pious tradition from seven centuries after Gregory.

(c) Reported miracles

Gregory is not chiefly remembered as a wonderworker. The Orthodox Church in America's life includes a few providential episodes, such as his rescue from the storm after a vow and a would-be assassin who came to him in tears of repentance. They cannot be checked independently; his holiness has always been located in his teaching and his willingness to give up power for peace. Part of his relics, kept in Rome for centuries, was returned to Ecumenical Patriarch Bartholomew by Pope John Paul II at St Peter's on 27 November 2004, a gesture the Pope hoped would help "to purify our wounded memories."³⁹

The Orthodox position

Dogma. Gregory's Trinitarian teaching is not his private opinion. The creed received from the council of 381 confesses the Holy Spirit as "the Lord and Giver-of-Life, who proceeds from the Father, who with the Father and the Son together is worshipped and glorified."⁴⁰ Gregory himself said more. He wrote that he held to the faith of Nicaea, "completing in detail that which was incompletely said by them concerning the Holy Ghost," that is, "confessing the Spirit also to be God."⁴¹ The Church has received his fuller language as the right reading of the creed. For what the councils decided, see The Seven Ecumenical Councils: What They Actually Decided; for how an Eastern council of 381 came to count as ecumenical, see How Does the Orthodox Church Know Which Councils Are Ecumenical?.

Common tradition. The Church keeps Gregory's feast on 25 January and the feast of the Three Hierarchs on 30 January.⁴² The Roman Catholic Church honors him with Basil on 2 January as a bishop and Doctor of the Church.⁴³

Theological opinion. Some of his ideas, such as his explanation of why revelation came gradually, are reasoning rather than dogma. Calling him "the Theologian" does not make every sentence he wrote binding.

The strongest objections

"Gregory admits the Spirit's deity is not plainly in Scripture"

Unitarians and some skeptics argue that Gregory gives the game away: if the New Testament only "suggested" the Spirit's deity, the doctrine is a later development. The objection is fair as far as it goes, since Gregory grants that "Scripture does not very clearly or very often write Him God in express words." His reply is that his opponents also rely on words not found in Scripture, such as "Unbegotten" and "Unoriginate," because they believe the meaning is there even where the word is not.⁴⁴ The question is whether the Scriptures, read as a whole in the Church's worship, require the conclusion. Our article Is the Trinity Biblical, or Was It Invented Later? sets out that evidence. Many Protestants have in fact welcomed Gregory: John Calvin wrote that "nothing can be more admirable than the words of Gregory Nanzianzen," quoting the passage on the One and the Three.⁴⁵

"Nicene orthodoxy won by imperial force"

This is a serious historical point. In 380 Theodosius decreed that his subjects should believe "in the one deity of the Father, Son and Holy Spirit, in equal majesty and in a holy Trinity," called dissenters "foolish madmen," and threatened them with punishment.⁴⁶ Gregory owed his enthronement to the emperor. But the Five Theological Orations were preached in the Anastasia, most likely before Theodosius reached the capital, to a small congregation without imperial support, and they persuaded by argument. Then he gave up the see rather than fight for it. {{moderate: His career suggests that the Nicene faith was held and argued for on its own terms before it had imperial power behind it.}} Christians today are free to judge Theodosius's laws severely.

"Gregory's theology fits the Filioque" (a Catholic reading)

Catholic theologians draw on Gregory to show that East and West share one faith about the Spirit. The Vatican's 1995 clarification calls him "a great witness to our two traditions," agrees that "the 'monarchy of the Father' implies that the Father is the sole Trinitarian Cause," and argues that the Filioque, rightly understood, does not contradict this.⁴⁷ Orthodox readers can welcome that real agreement. The Orthodox reply is that Gregory's own formula is that the Spirit "proceeds from the Father," as the unaltered creed says, and that adding "and the Son" to the creed without a council of the whole Church remains the problem. Our article on the Filioque covers the debate.

"A saint who complained so much?"

Readers sometimes find Gregory vain and touchy. But sainthood has never meant a flawless personality. His complaints sit beside real sacrifices: he gave his inheritance to the poor,⁴⁸ accepted burdens he did not want, and resigned the capital's see for the sake of peace. That he left an honest record of his own frailty is part of why he is trusted.

What we can say confidently

• Gregory was a Cappadocian bishop of the late fourth century, a close friend of Basil of Caesarea, and the author of many surviving orations, letters and poems.
• He led the Nicene congregation in Constantinople from 379, preached the Five Theological Orations there, and was enthroned as the city's bishop in late 380.
• He presided over part of the council of 381 and resigned during it.
• He taught plainly that the Holy Spirit is God, consubstantial with the Father and the Son, and that the Father is the one source of the Son and the Spirit.

What remains disputed

• His exact years of birth (about 325 to 330) and death (389 to 391), and when he was baptized.
• The sequence of events in 380 and 381, where Gregory, Socrates and Theodoret differ.
• How and when the title "the Theologian" was first attached to him.
• How fairly his self-defending poems portray Basil, Maximus and the bishops of 381.
• Whether his teaching can be reconciled with the Western Filioque, as Catholic theologians argue and Orthodox theologians generally doubt.

Conclusion

Gregory never wanted to be a public man. Yet in about two years in Constantinople, preaching in a borrowed house, he gave the Church words for the faith it had always worshipped: one God, Father, Son and Holy Spirit, the Spirit fully God, the Father the one source.

The Church calls him the Theologian because his theology is prayer. He ended his farewell to Constantinople not with a defense of himself but with a goodbye to the Trinity, "my meditation, and my glory." More of the Fathers who shaped that faith can be explored in the Church Fathers Explorer and the Lives of the Saints.

Notes

1. Orthodox Church in America (OCA), "Saint Gregory the Theologian, Archbishop of Constantinople" (25 January), Lives of the Saints, oca.org. ↩
2. Gregory of Nazianzus, Oration 43 (Funeral Oration on Basil), 14 and 20, trans. Charles Gordon Browne and James Edward Swallow, NPNF2 vol. 7 (1894), revised at newadvent.org. ↩
3. O. Hunter-Blair, "St. Gregory of Nazianzus," Catholic Encyclopedia, vol. 7 (1910). ↩
4. Hunter-Blair, "St. Gregory of Nazianzus" (some biographers infer baptism during the storm, "though the fact is not certain"; there is "some authority" for a later baptism at home); Browne and Swallow, Prolegomena, "The Life" (a later baptism "most probable"); OCA, "Saint Gregory the Theologian" (baptized by his father at thirty-three). ↩
5. Gregory, Oration 2 (In Defence of His Flight to Pontus), 16, NPNF2 vol. 7, with the editors' introduction (ordination "on Christmas Day A.D. 361"; later use by Chrysostom and Gregory the Great). Hunter-Blair gives "probably at Christmas, 361." ↩
6. Hunter-Blair, "St. Gregory of Nazianzus"; Browne and Swallow, Prolegomena to NPNF2 vol. 7, "The Life." ↩
7. Gregory, Epistle 48, to Basil, NPNF2 vol. 7. ↩
8. Browne and Swallow, Prolegomena, "The Life" ("it is probable he never actually administered" Sasima). ↩
9. Gregory, Oration 43.59, NPNF2 vol. 7. ↩
10. Browne and Swallow, Prolegomena, "The Life"; Hunter-Blair, "St. Gregory of Nazianzus." ↩
11. Gregory, Oration 42 (The Last Farewell), 26, NPNF2 vol. 7. ↩
12. OCA, "Saint Gregory the Theologian" (gives the date as Pascha, 21 April 379); Hunter-Blair also reports the attack during the Easter baptisms. ↩
13. Jerome, Lives of Illustrious Men 117, trans. Ernest Cushing Richardson, NPNF2 vol. 3 (1892), revised at newadvent.org. ↩
14. Hunter-Blair, "St. Gregory of Nazianzus." Jerome, Lives of Illustrious Men 117, lists a work "In praise of Maximus the philosopher" and notes that another work by Gregory upbraids the same Maximus. ↩
15. First Council of Constantinople (381), Canon 4, trans. Henry Percival, NPNF2 vol. 14 (1900), revised at newadvent.org. ↩
16. Socrates Scholasticus, Church History 5.6-7, trans. A. C. Zenos, NPNF2 vol. 2 (1890), revised at newadvent.org (arrival on 24 November, the churches handed over on 26 November); Hunter-Blair, "St. Gregory of Nazianzus" (the emperor accompanied Gregory to St Sophia). ↩
17. Socrates, Church History 5.8; Theodoret, Ecclesiastical History 5.8, trans. Blomfield Jackson, NPNF2 vol. 3 (1892), revised at newadvent.org; Browne and Swallow, Prolegomena, "The Life" (the council met "under the presidency of Meletius"). ↩
18. Hunter-Blair, "St. Gregory of Nazianzus," summarizing Gregory's poem Concerning His Own Life. The poem itself was not opened for this article. ↩
19. Gregory, Oration 42.24, NPNF2 vol. 7. ↩
20. Gregory, Oration 42.27, NPNF2 vol. 7. On Nectarius: Socrates, Church History 5.8 (senatorial family, then holding the office of "proctor"); Browne and Swallow, Prolegomena ("only a catechumen"). ↩
21. Browne and Swallow, Prolegomena, "The Life." ↩
22. Editors' introduction to Epistle 131, NPNF2 vol. 7 (the letter to Procopius declining the synod of 382 is summarized there, not translated). ↩
23. Carolinne White, ed. and trans., Gregory of Nazianzus: Autobiographical Poems (Cambridge University Press, 1996), contents ("Concerning his own life (II 1.11)") and publisher's description. ↩
24. Jerome, Lives of Illustrious Men 117. ↩
25. Gregory, Oration 27 (First Theological Oration), 3, NPNF2 vol. 7. On the Eunomians, OCA, "Saint Gregory the Theologian." ↩
26. Gregory, Oration 28 (Second Theological Oration), 4, NPNF2 vol. 7. ↩
27. Gregory, Oration 29 (Third Theological Oration), 2, NPNF2 vol. 7. ↩
28. Gregory, Oration 31 (Fifth Theological Oration), 8, NPNF2 vol. 7; John 15:26, NKJV. ↩
29. Gregory, Oration 31.10, NPNF2 vol. 7. ↩
30. Gregory, Oration 31.26, NPNF2 vol. 7. ↩
31. Gregory, Oration 40 (On Holy Baptism), 41, NPNF2 vol. 7. ↩
32. Gregory, Epistle 101 (First Letter to Cledonius), NPNF2 vol. 7. ↩
33. Browne and Swallow, Prolegomena, "The Life." The OCA life of Gregory likewise notes that the title is also given to the Apostle John. ↩
34. Oliver B. Langworthy, "Theodoret's Theologian: Assessing the Origin and Significance of Gregory of Nazianzus' Title," Journal of Ecclesiastical History 70, no. 3 (2019): 455-71, doi:10.1017/S0022046918001951. ↩
35. Jerome, Lives of Illustrious Men, preface and 117. The conversion of Theodosius's fourteenth year to 392/393 is ours. ↩
36. Socrates, Church History 5.7. ↩
37. OCA, "Saint Gregory the Theologian"; Hunter-Blair, "St. Gregory of Nazianzus"; CatholicCulture.org, Liturgical Year, 2 January; Browne and Swallow, Prolegomena, "The Life." ↩
38. OCA, "Synaxis of the Ecumenical Teachers and Hierarchs: Basil the Great, Gregory the Theologian, and John Chrysostom" (30 January), oca.org. ↩
39. John Paul II, "Ecumenical Celebration on the Occasion of the Transferral from Rome to Constantinople of the Relics of Sts Gregory of Nazianzen and John Chrysostom: Letter of John Paul II to the Ecumenical Patriarch of Constantinople," 27 November 2004, 2, vatican.va. ↩
40. Creed of the First Council of Constantinople (381), trans. Henry Percival, NPNF2 vol. 14. ↩
41. Gregory, Epistle 102 (Second Letter to Cledonius), NPNF2 vol. 7. ↩
42. OCA, Lives of the Saints, 25 and 30 January. ↩
43. CatholicCulture.org, Liturgical Year, 2 January, "Memorial of St. Basil the Great and St. Gregory Nazianzen, Bishops and Doctors." ↩
44. Gregory, Oration 31.21 and 23-24, NPNF2 vol. 7. ↩
45. John Calvin, Institutes of the Christian Religion 1.13.17, trans. Henry Beveridge (1845), ccel.org. Calvin cites the passage as from Gregory's sermon on holy baptism (Oration 40.41). ↩
46. Theodosian Code 16.1.2, in Henry Bettenson, ed., Documents of the Christian Church (Oxford University Press, 1943), 31, as reproduced in the Internet Medieval Sourcebook (Fordham University). Spelling and capitals corrected from the online transcription ("diety," "father"). ↩
47. Pontifical Council for Promoting Christian Unity, "The Greek and Latin Traditions Regarding the Procession of the Holy Spirit" (1995), as reproduced at catholicculture.org. ↩
48. Hunter-Blair, "St. Gregory of Nazianzus" (after his parents' deaths he "devoted to the poor the large fortune which he had inherited"). ↩

Bibliography

Primary sources

• Gregory of Nazianzus. Orations 2, 27-31, 40, 42 and 43. Translated by Charles Gordon Browne and James Edward Swallow. Nicene and Post-Nicene Fathers, 2nd series, vol. 7. Buffalo, NY: Christian Literature Publishing Co., 1894. Revised edition at newadvent.org.
• Gregory of Nazianzus. Letters (Epistles 48, 101, 102 and the editors' introduction to 131). Translated by Charles Gordon Browne and James Edward Swallow. NPNF2 vol. 7, 1894. Revised edition at newadvent.org.
• Gregory of Nazianzus. Autobiographical Poems. Edited and translated by Carolinne White. Cambridge Medieval Classics 6. Cambridge: Cambridge University Press, 1996.
• Jerome. Lives of Illustrious Men. Translated by Ernest Cushing Richardson. NPNF2 vol. 3. Buffalo, NY: Christian Literature Publishing Co., 1892.
• Socrates Scholasticus. Church History, Book 5. Translated by A. C. Zenos. NPNF2 vol. 2. Buffalo, NY: Christian Literature Publishing Co., 1890.
• Theodoret of Cyrrhus. Ecclesiastical History, Book 5. Translated by Blomfield Jackson. NPNF2 vol. 3. Buffalo, NY: Christian Literature Publishing Co., 1892.
• First Council of Constantinople (381). Creed and canons. Translated by Henry Percival. NPNF2 vol. 14. Buffalo, NY: Christian Literature Publishing Co., 1900.
• Theodosian Code 16.1.2. In Documents of the Christian Church, edited by Henry Bettenson. London: Oxford University Press, 1943.
• The Holy Bible, New King James Version. Nashville: Thomas Nelson, 1982.

Orthodox and patristic sources

• Orthodox Church in America. "Saint Gregory the Theologian, Archbishop of Constantinople" (25 January) and "Synaxis of the Ecumenical Teachers and Hierarchs" (30 January). Lives of the Saints, oca.org.
• Browne, Charles Gordon, and James Edward Swallow. Prolegomena, "The Life." NPNF2 vol. 7, 1894. ccel.org.
• John Paul II. "Ecumenical Celebration on the Occasion of the Transferral from Rome to Constantinople of the Relics of Sts Gregory of Nazianzen and John Chrysostom: Letter of John Paul II to the Ecumenical Patriarch of Constantinople His Holiness Bartholomew I." 27 November 2004. vatican.va.

Other scholarship (including scholars who disagree)

• Langworthy, Oliver B. "Theodoret's Theologian: Assessing the Origin and Significance of Gregory of Nazianzus' Title." Journal of Ecclesiastical History 70, no. 3 (2019): 455-71.
• Hunter-Blair, O. "St. Gregory of Nazianzus." The Catholic Encyclopedia, vol. 7. New York: Robert Appleton Company, 1910.

Sources from the traditions discussed (Catholic and Protestant)

• Pontifical Council for Promoting Christian Unity. "The Greek and Latin Traditions Regarding the Procession of the Holy Spirit." 1995.
• CatholicCulture.org. Liturgical Year, 2 January: "Memorial of St. Basil the Great and St. Gregory Nazianzen, Bishops and Doctors."
• Calvin, John. Institutes of the Christian Religion. Translated by Henry Beveridge. Edinburgh: Calvin Translation Society, 1845. Book 1, chapter 13.